The Behavior And Its Mechanisms Of Host Preference Of Apolygus Lucorum (Meyer-Dur) To Mungbean Plants

Apolygus lucorum (Hemiptera:Miridae) is a polyphagous insect, and has more than120species of host plants. At present, A. lucorum is an important insect pest of various host crops (inc. cotton, grape, Chinese date) and causes serious damage in their annual production. A. lucorum shows great preference to mungbean plants, but the intrinic mechanism is little known. This study is to explore the behavioral and chemical mechanisms of A. lucorum’s preference to mungbean plants, and to develop attractants for the trapping management of A. lucorum adults. The main results are listed as follows:We compared the oviposition preference of A. lucorum on mungbean versus cotton plants in both open-field plots and field cages. Field-plot experiments demonstrated that the population density of first-instar nymphs and adults of A. lucorum and the ratio of first-instar nymphs to adults were significantly higher on mungbean than cotton. Choice and no-choice cage experiments revealed that the number of eggs laid on mungbean was significantly higher than on cotton. We also compared adult longevity and fecundity, as well as offspring survival and developmental rate on these two host plants. We found that A. lucorum adult females survived longer and laid more eggs on mungbean than on cotton. Mungbean also promoted higher rates of development than did cotton, but did not affect nymphal survival. In summary, the preference of A. lucorum adults for mungbean is consistent with the both adult and nymphal performance.Y-olfactometer trials indicated that A. lucorum adults preferred mungbean plants to cotton plants, and the ratio of A. lucorum selecting mungbean plants is higher than that on cotton plants. We determined the substance peaks of mungbean volatile compositions, which caused electrophysiological responses of the antenna of A. lucorum through coupled gas chromatography-electroantennographic detection (GC-EAD) and gas chromatography-mass spectrometry (GC-MS). Seven active volatile compositions were identified, including Ethylbenzene,1,3-dimethylbenzene,2-Propenoic acid, butyl ester, Propanoic acid, butyl ester, Butanoic acid, butyl ester,(E)-3-Hexenyl acetate, and Benzene,1-ethyl-4-(2-methylpropyl)-o The Y-olfactometer test indicated that A. lucorum adults showed obvious taxis to1,3-dimethylbenzene,2-Propenoic acid, butyl ester, Propanoic acid, butyl ester, Butanoic acid, butyl ester, Benzene,1-ethyl-4-(2-methylpropyl)-, but not for Ethylbenzene and (E)-3-Hexenyl acetate.A. lucorum adults hovered near the top part of cotton plants, mostly at20-cm height above the cotton top. During the whole day, A. lucorum adults showed evident activity mainly from the evening to wee hours. The Propanoic acid, butyl ester and Benzene,1-ethyl-4-(2-methylpropyl)-that identified from mungbean plants could effectively trap A. lucorum adults. The mean number of A. lucorum trapped by Propanoic acid, butyl ester and Benzene,1-ethyl-4-(2-methylpropyl)-was4.2±1.15and3.8±1.27per trap per3days, respectively, which was significantly higher than that of the control (0.25±0.25). However, no significant differences were found between1,3-dimethylbenzene,2-Propenoic acid, butyl ester, Butanoic acid. butyl ester and the control.